1、 Overview of the Development of Artificial Diamond Industry
The chemical composition of diamond is carbon (C), which is a Allotropy of carbon element with a density of 3.52g/cm ³、 The hardness is Mohs 10, which is currently the hardest substance known to humans in nature. Diamonds can be divided into natural diamonds and artificial diamonds based on their genesis.
Natural diamond is a rare and valuable non-metallic mineral, among which gem grade diamonds with high quality and large grain size that can be used to make jewelry are called natural diamonds. Natural diamond primary ores are mainly distributed in South Africa, Zaire, Botswana, Russia, Australia and other countries, with low mineral reserves and great difficulty in mining. The natural diamond mine is a non Renewable resource and has the characteristics of scarce mineral reserves, high mining costs and high degree of damage to the ecological environment during the mining process. It cannot be widely used in the industrial field. Therefore, the global industrial diamond is mainly artificial diamond.
Artificial diamond, as an advanced carbon material, not only has excellent mechanical properties such as superhard, wear-resistant, and corrosion-resistant properties, but also has unparalleled thermal, optical, acoustic, electrical, and chemical properties compared to other materials. It is an efficient, high-precision, semi permanent, energy-saving, green and environmentally friendly material, which greatly supports other high-tech industries and enjoys the reputation of "the king of materials". With the continuous improvement of synthetic diamond technology, the larger and higher quality single crystals in large diamond crystals are used in the consumer field to cultivate diamonds for making diamond inlaid jewelry or other fashionable consumer goods. Cultivated diamonds and natural diamonds are both crystals formed from carbon elements, with the same chemical and physical properties. Cultivated diamonds can rival natural diamonds in terms of crystal structure integrity, transparency, refractive index, dispersion, and other aspects. Cultivating diamonds as a new force in the diamond industry provides a new choice for consumers who love diamonds. With the continuous improvement of diamond synthesis technology, the advantages of cultivating diamonds in product quality, production costs, and controllability in grade, size, color, customization, and other aspects are becoming increasingly prominent, with huge development potential.
2、 Synthetic Method of Artificial Diamond
Artificial diamond is a diamond crystal synthesized using scientific methods by artificially simulating the crystallization conditions and growth environment of natural diamonds. The main synthesis methods are high-temperature high-pressure (HTHP) and chemical vapor deposition (CVD).
The development of Chemical Vapor Deposition (CVD) method is not a substitute for High Temperature and High Pressure (HTHP) method, as they adopt completely different synthesis principles and technologies, and produce different types and characteristics of products. The main industrial applications also focus on different terminal fields. In terms of the actual development situation of China's artificial diamond industry at present, the high-temperature high-pressure method (HTHP) is mainly used. In the future, the high-temperature high-pressure method (HTHP) and chemical vapor deposition method (CVD) will maintain a common development trend, which is the basic feature of the artificial diamond industry. High temperature and high pressure method (HTHP) has been industrialized since the 1950s. Its synthesis principle is that graphite powder undergoes phase transformation and grows diamond crystals under ultra-high temperature and high pressure conditions and the catalytic action of metal catalyst powder. The synthetic diamond synthesized by this method is mainly granular single crystals, with fast synthesis speed, high single output, and good economic performance. Its industrial application mainly utilizes diamond superhard, wear-resistant, and Produce machining tools such as grinding, sawing, and drilling with mechanical characteristics such as corrosion resistance. In 1965, China's independently developed diamond hexahedral top press was introduced and quickly promoted on a large scale in China. The production efficiency and production capacity of artificial diamond products were rapidly improved, and China quickly became the largest country in diamond single crystal production; In recent years, the large-scale synthesis press, powder catalyst technology, and high-temperature and high-pressure synthesis process have further established China's leading advantages in synthesizing diamond single crystals under high-temperature and high-pressure methods. Major diamond single crystal producers in the industry, such as Zhongnan Diamond, Huanghe Cyclone, Yu Diamond, and Liliang Diamond, all use the high-temperature and high-pressure method (HTHP). After more than half a century of development, the high-temperature and high-pressure method technology has become relatively mature. With the large-scale synthesis equipment and continuous improvement of synthesis technology, the diamond single crystals synthesized by this method have made significant progress in particle size, crystal form integrity, purity, strength, and other aspects; However, due to the structural design of high-pressure equipment, the size of diamond single crystals synthesized is relatively small, which to some extent limits their widespread application in functional materials. With the continuous development of large particle single crystal synthesis technology, there have been research results on high-temperature and high-pressure synthesis of single diamond single crystals of over 100 carats internationally. It is expected to make certain breakthroughs in the application of functional materials in the future.
The chemical vapor deposition (CVD) method has been studied and industrially applied since the 1980s. Its synthesis principle is that a mixture of carbon containing gas (CH4) and hydrogen is excited and decomposed into activated carbon atoms under ultra-high and low pressure conditions. By controlling the deposition and growth conditions, the activated carbon protons are deposited and grown alternately on the substrate to form diamond crystals. The diamond synthesized under this method is mainly sheet-like diamond, Its industrial application mainly utilizes the performance advantages of diamond in the fields of light, electricity, magnetism, sound, and heat as functional materials in emerging industries. At present, countries such as the United States, Japan, and Singapore have achieved significant results in the research and industrial application of Chemical Vapor Deposition (CVD) technology. Although China has introduced relevant industry policies at the national level to provide significant support and encouragement for CVD technology, it is currently affected by factors such as limited downstream application demand, slow progress in technology research and development, and the monopoly of advanced technology by a few enterprises, The development speed of chemical vapor deposition (CVD) technology research and industrial application is relatively slow, and as of now, there are relatively few units in China that have achieved outstanding results in the research and industrial application of chemical vapor deposition (CVD) technology. The comparison of the characteristics of high-temperature high-pressure method (HTHP) and chemical vapor deposition method (CVD) in synthesis technology, synthesis results, and product applications is shown in the table below: Chart Comparison of the Characteristics of HTHP Method and CVD Method
From the above table, it can be seen that there are significant differences in the characteristics of synthesis technology, synthesis results, and product applications between the High Temperature High Pressure (HTHP) method and the Chemical Vapor Deposition (CVD) method. Due to the fact that chemical vapor deposition (CVD) can only grow on substrates with crystal seeds during the synthesis of diamond single crystals, it belongs to two-dimensional growth and can only grow monolayers. It is not suitable for synthesizing small particle single crystals and cannot meet the demand for diamond single crystals in the industrial field. Therefore, it will not replace the high-temperature high-pressure method (HTHP) in industrial applications. In terms of cultivating diamond synthesis, based on existing technical conditions, the high-temperature high-pressure method (HTHP) synthesis cultivates diamonds mainly in the form of towers, with fast growth speed, low cost, and slightly lower purity. However, it has advantages in comprehensive benefits, especially in the 1-5ct cultivation of diamond synthesis; The chemical vapor deposition (CVD) method is used to synthesize cultivated diamonds in a plate-like shape, which is difficult to control in color, has a long cultivation cycle, and high cost. However, it has a high purity and is more suitable for diamond synthesis above 5ct. Therefore, in the field of diamond single crystal synthesis, the chemical vapor deposition (CVD) method will not replace the high-temperature high-pressure method (HTHP); In the field of cultivating diamond synthesis, the two focus on different types of products and do not constitute a substitute relationship.
3、 Industry Application Fields of Artificial Diamond
Artificial diamond has excellent performance in mechanics, thermodynamics, optics, acoustics, electronics, and chemistry, and has a wide range of terminal applications, mainly including industrial applications and fashion consumption applications.
1. Industrial applications
The industrial application of artificial diamond mainly includes two aspects. One is to use the mechanical properties of artificial diamond, which is super hard, wear-resistant and corrosion resistant, to make various diamond tools such as grinding, cutting, cutting, etc., which can be used for processing metal and alloy materials, high hard and brittle materials (silicon, sapphire, magnetic materials, etc.), soft and tough materials (rubber, resin, etc.), and other difficult to process materials; The second is to utilize the special properties of artificial diamonds in light, electricity, sound, magnetism, heat, and other aspects, as important functional materials, applied in high-tech fields such as electronics, equipment manufacturing, aerospace, national defense and military industry, medical testing and treatment. Diamond tools can generally be divided into sawing tools, grinding tools, and drilling tools according to their usage. Sawing tools mainly include saw blades, saw blades, rope saws, wire saws, cutting tools, etc; Grinding tools refer to tools made of diamond as abrasive and with the help of binders or other auxiliary materials under certain production conditions, which have a certain shape and performance and can be used for grinding, grinding, polishing, and other purposes. Their product types are mainly divided into three categories: fixed grinding tools, coated grinding tools, and paste liquid grinding tools, including grinding wheels, grinding heads, cutting pieces, grinding discs, oilstones, abrasive cloth, abrasive belts, polishing films, grinding paste, grinding fluids, etc; Drilling tools mainly include geological drill bits, oil (gas) well drill bits, and engineering thin-walled drill bits, which are respectively applied to geological exploration, oil (gas) exploration and production, and various types of building drilling. The above-mentioned diamond tools are widely used in the cutting, cutting, grinding, and drilling of various materials such as stone, glass, ceramics, silicon wafers, hard metals, alloys, gemstones, agate, jade, etc. Their terminal applications have covered many fields such as building materials, stone materials, equipment manufacturing, automotive manufacturing, household appliances, electronic appliances, clean energy, exploration and mining, etc. The development of technology has led to the emergence of emerging applications of artificial diamonds as functional materials. Artificial diamond, as a widely used extreme material, can not only process various difficult to machine materials, but is also developing towards functional components such as high sensitivity, high precision, high power, high transparency, high heat conduction, high electron migration, high human affinity, high wear resistance, corrosion resistance, and radiation resistance. Diamond has special properties in optical, electrical, acoustic, thermal, and other fields. As an important functional material, it has also attracted increasing attention, and its properties and applications are constantly being researched and developed.
2. Application in the field of fashion consumption
Large single crystals of gemstone grade diamond with a certain standard in color, weight, and purity in artificial diamonds can be used as cultivation diamond inlay jewelry in the consumer field. After design, cutting, polishing, and processing, cultivation diamonds can be made into various dazzling diamond jewelry. Cultivated diamonds and natural diamonds have identical chemical composition, color, clarity, and other physical properties except for their different growth environments. However, the sales price of cultivated diamond jewelry is approximately 30% to 50% of the sales price of natural diamond jewelry of the same grade. In recent years, with the development of diamond synthesis technology and the improvement of consumer awareness of diamond cultivation, diamond cultivation has been increasingly applied to wearing accessories, craft decorations, and art collectibles.
